Boiler



May 21, 1935. H. J. KERR El AL B ILER Oiiginal Filed Dec. 6,-1928 INVENTOR5 2 Q 5 x Z w a 9 x O 3 z 4 W 0 w ,7. 4 O a I 7 O 0 0 Al 0 j v W W ATTORNEYS Patented May 21, 1935 i.

s PATENT OFFICE BOILER Howard J. Kerr, Westfield, N. J., and Ivar L.

Langvand, Barberton, Ohio, assignors to The Babcock & Wilcox Company, Bayonne, N. J., a corporation of New Jersey Application December 6, 1928, Serial No. 324,084 a Renewed June 26, 1934 J 10 Claims. (ol. 122-302) The invention relates particularly to boilers of to. the lowerdrum by. banks of tubes which are the so-called Stirling type, and will be described substantially parallel to each other and spaced in reference thereto. The accompanying drawapart a greater portion of their lengths. In. the ing indicates a vertical sectional viewthrough a parallel sided space thus formed between the j UNITED: STATE boiler showing an embodiment of the invention. front and middle banks, is-disposed a superheater 5 For the purposes of illustration, the invention here shown as aplurality of U-tubes 25, conis shown as embodied in a Stirling boiler having nected to inlet and outlet headers 26 and 21 a lower water drum I, and front, middle and rear. respectively, and substantially uniformly disupper steam and water drums 2, 3 and 4 respec-. posed across the space and filling the space. Ex-

10,. tively. Each of the upper drums is connected tending upwardly from the lower water drum and tothe lower drum by a bank of tubes, a front along the rear of the bank 5 is a baflie 28 conbank 5, a middle bank 6, and a rear bank I servnected by across bafiie 29 to a bafiie 30 on the ing to connect the front, middleand rear upper front of the middle bank. This arrangement drums respectively to the lower drum. In front provides a tapering gas pass through which i of the frontbank of tubes is a source of heat ingases flow, contacting successively with the bank 15 dicated as a grate 8 beneath an arch 9, although 5, the superheater and the middle bank 6. The it is to be understood that. any other suitable gases then flow into the second pass which insource of heat may be supplied. cludes the tubes of the middle bank and which The hot gases from the source of heat are is defined between the baflie 30 and a second bat-t directed upwardly over the front bank of tubes, fie 3|, and then pass upwardly overthe rear bank 20 downwardly over the middle bank, and upwardly and out the flue. i I over the rear bank to the flue H). For this pur- It has been found that the arrangements depose, suitable baiiiing is provided and in the form scribed .aboveproduce improved results in sevshown, this baffling comprises a bafiie 30 disposed eral respects. Priming is lessened, for one thing.

on the front row of the middle bank. Thewater level in the outlet or rear upper drum 25 Disposed adjacent the rear ofthe bank 6 is a is maintained sufiiciently low to greatly reduce baflie 3! which with the baflie forms the second priming and the water separated from the steam pass through which gases flow over the bank 6, in the front and middle drums may return to this bank being included in that pass. The rear the bottom drum through tubes in av cooler pass 30 bank I connects the lower drum with the rear directly withoutthe necessity for passing to the 30 upper drum 4, and-some of the tubes 1 are carnext rearward upper drum. The superheater ried forward and are connected to the .middle arranged between parallel banks of tubes, and d um 3. These tu s ay e-us d to supp rt filling the space and. avoiding gas short cir- & b fl e cuits, makes possible a more compact efiioient By t a ve ran m n there is p vid d structure than Where the banks of tubes are 35 a plu al t f tu s connecting e o t front disposed at angles to each other, or where the an mid l upp drums the lower Water drum, space between banks is not filled, as is the usual and the tubes Connecting one h practice. This arrangement, particularly in comdrums F the lfiwer druma some dlsposefiln bination with the tapered gas pass over the 40 a relatlvely hot pass Others m airelatltely superheater andoppositebanks of tubes, results 40 cool pass. For example of the tubes connecting in aboner which is of high capacity, high the lower drum .to the upper front drum, some I are exposed to the hot gases in the combustion clency and h leasivamtwn Superheat as the load changes.

chamber, whileothers .are disposed in the second pass where they are subjected to the Same gase While there has been shown a certain selected after they have been cooled by contact with the e d t of the invention, it is to be under- 45 fr nt; b k of t b p I stood that the invention is not limited to this The drums 3 and 4 are connected by steam' embodiment, but o y by the 500190 of h pcirculators l1 and the drums 2 and 3 by steam pended claims. circulators l8 and water circulators l9,,although We 'claim:'- 50 the latter may b omitt d under certain'condi- 1. Ina Stir1ing type boiler, the combination tions. The rearupper drum is. provided with 'a of'a. rear steam off-take drum, a middle drum, a steam outlet 20 and also with-a feed water inlet front drum, a lower drum, a baffle separating a 2L- o high temperature gas pass from a low tempera- The front and mi d lI B Q i fi i ture gas pass, a first group of tubes in the latter 55 gas pass directly connecting the lower and offtake drums and constituting the only direct connections between said drums, a second group of tubes in the low temperature gas pass directly connecting the lower and middle drums, a third group of tubes in the high temperature gas pass directly connecting the lower and middle drums, a furnace, a second bafiie for the third group of tubes, a divided bank of tubes above the furnace and partly in front of the second bafiie so as to be exposed to the radiant heat from the furnace gases, a superheater located between the divisions of the said last mentioned bank of tubes, and steam circulators directly connecting the middle and off-take drums, said first and second groups of tubes constituting the only connections between the water spaces of the middleand offtake drums, said combination acting to decrease the water level in offtake drum with increase in capacity at which boiler is operated.

2. In a water tube steam boiler a boiler setting, a middle steam and water drum located between two similar drums at the top of the setting, a water chamber below said drums, tubes leading from said drums to the water chamber, baffles dividing the tubes into a plurality of separated banks located in separate gas passes extending through the setting, a lower number of the tubes in a bank leading to a drum from which a greater number of tubes extend downwardly through an adjacent gas pass of higher temperature, the tubes in each bank being bent at their upper ends so as to constitute diverging groups of tubes, secondary bafiies between adjacent upper drums and having diverging portions extending along diverging tubes of said diverging groups oftubes, said secondary baffies forming gas pass walls guiding the furnace gases at their turns, a steam off-take connection communicating with the steam space of the rear upper drum, the middle upper drum having no water circulators directly connecting it with the rear upper drum, and steam circulato-rs connecting the steam spaces of the rear and front upper drums to the steam space of the middle drum, water circulator tubes directly connecting the front and middle upper drums, a furnace, and a steam superheater located in the first gas pass from the furnace, the only water circulator connections between the middle and rear upper drums being through said groups of tubes which provide recirculation in the upper drums.

, 3. In a bent tube steam boiler including two natural circulation systems, a common boiler furnace, a separate steam and water drum for each system, a mud drum common toboth systerns, steam generating tubes for each system connecting the mud drum directly with the steam and water drum, downcomer tubes connecting each steam and water drum to the mud drum and exposed to furnace gases at temperatures lower than those of the gases contacting with the generating tubes leading to the same steam and water drum, an oiftake steam and water drum having at increased ratings an effective steam space greater than the steam space of either of the other steam and water drums, steam circulators directly connecting the offtake drum and one of the first mentioned steam and water drums and constituting the only direct connection between them, other steam circulators directly connecting the steam and water drums, downcomer tubes directly connecting the offtake drum with the mud drum, an offtake drum feed water connection discharging feed Water into the ofltake drum, a superheater between the downcomer tubes and the steam generating tubes connected to the front drum of said steam and water drums, a rear bafiie starting at the mud drum and extending upwardly along the rear tubes of the steam generating tubes leading from the mud drum to the front steam and Water drum and terminating short of the front steam and water drum, and a bafile terminating short of the mud drum and located rearwardly of the superheater.

4. In a Stirling type boiler, the combination of a rear steam off-take drum, a middle drum, a front drum, a lower drum, a battle separating a rear gas pass from a middle gas pass, a first group of tubes in the rear gas pass directly connecting the lower and off-take drums and constituting the only direct connections between said drums, at second group of tubes in the rear gas pass directly connecting the lower and middle drums, a third group of tubes in the middle gas pass directly connecting the lower and middle drums, a furnace, a second baflle in front of the third'group of tubes, a divided bank of tubes above the furnace and partly in front of the second bafile so as to be exposed to the radiant heat from the furnace gases, the divided bank of tubes directly connecting the front and lower drums, a superheater located between the divisions of the said last mentioned bank of tubes, and steam circulators comiecting the steam spaces of the middle and front and offtake steam and water drums said combination acting to increase the separation space of the off-take drum in proportion to the increase in capacity at which the boiler is operated.

5. In a Stirling type boiler, the combination of a rear steam off-take drum, a middle drum, a front drum, a lower drum, a bafiie separating a middle gas pass of high temperature from a rear gas pass of low temperature, a first group of tubes in the rear gas pass directly connecting the lower and off-take drums and constituting the only direct connections between said drums, a second group of tubes in the rear gas pass directly connecting the lower and middle drums, a third group of tubes in the middle gas pass directly connecting the lower and middle drums, a furnace, a second bafile in front of the third group of tubes, a divided bank of tubes above the furnace and partly in front of the second bafile so as to be exposed to the radiant heat from the furnace gases, the divided bank of tubes directly connecting the front and lower drums, a superheater located between the divisions of the said last mentioned bank of tubes, and steam circulators confiecting the steam spaces of the middle and front and off-take drums, said combination acting to increase the separation space of the off-take drum in proportion to the increase in capacity at which the boiler is operated.

6. In combination, a bent tube boiler having a mud drum, upper steam and water drums and banks of tubes connecting said drums including a front bank the tubes of which connect the mud drum and the front steam and water drum, and a second bank certain of the tubes of which connect the mud drum and a second steam and water drum and other tubes of which connect the mud drum and the front steam and water drum, said banks of tubes being so bent asto provide a substantial space therebetween for the major part of the longitudinal extent of the banks of tubes, a steam heater in said space, a rear baflie for the front bank beginning at the mud drum and below the upper drums into gas passes of different terminating short of the front steam and water drum, and a front battle for the second bank terminating short of the mud drum and extending substantially parallel to the second bank.

'7. In a water tube steam boiler of the Stirling type three upper drums including a front and rear drum, a lower drum, a front bank of inclined steam generating tubes directly connecting the front drum to the lower drum, 2, second. bank of tubes connecting the lower drum to the two forward upper drums and having their lower portions extending from the lower drum at a considerable angle away from the general direction of the tubes of the front bank and their main portions spaced substantially rearwardly of the front bank of tubes and extending generally parallel thereto towards the upper drums, and a third bank of tubes communicating with the lower drum at positions rearwardly of the second bank and having lower substantially straight portions extending substantially vertically from lower drum and forming with the lower portions of the second bank a substantially continuous tube bank,

the remaining portions of the tubes of the third bank being bent substantially forwardly from their lower portions and extending upwardly towards the upper drums.

8. In a water tube boiler of the bent tube type, a furnace, a first main natural circulation system including an upper drum and a lower drum directly connected by tubes in two separated and spaced groups exposed to heating gases at different temperatures, one group constituting steam generators exposed directly to heat from the furnace, a second main natural circulation system distinct from the first and including a separate upper drum directly connected to the above mentioned lower drum by tubes separated into two groups one of which is exposed to heating gases in the same gas pass as one of the groups of the first mentioned tubes, baflie interposed relative to the two groups of tubes in the second system, a third upper drum, a steam off-take connection above and leading from the third drum, a bank of tubes directly connecting the third drum to the lower drum and exposed to heating gases after they have contacted with the tubes of the other groups, steam circulators connecting the steam spaces of the upper drums and a superheater positioned forwardly of the baffle and rearwardly of tubes of one of said first mentioned groups of tubes, the steam and water separation for the boiler taking place in two main stages with a primary stage independently taking place in the drum for each circulation system and a secondary separation common to both systems and taking place in the third drum.

9. A water tube boiler including a lower drum, three upper steam and'water drums including a rear drum, a furnace, bailles dividing the gas space temperatures, a bank of tubes directly connecting the lower drum with the front steam and water drum and disposed in the gas pass nearest the furnace and of highest temperature, tubes directly connecting the lower drum with the front drum and disposed in a second gas pass of lower temperature than the first, tubes in a third gas pass directly connecting the rear drum and the lower drum, separated groups of tubes connected to the middle upper drum and the lower drum and subjected to heat from the furnace gases at separated positions of materially different temperatures, circulators directly connecting the steam spaces of the upper drums, and a superheater positioned rearwardly of tubes of the first mentioned bank of tubes and forwardly of. said bafiles, the steam and water separation for the boiler'taking place in two main stages with a primary stage taking place in each of the middle and front upper drums and a secondary separation common to both independent primary separations taking place in the rear drum.

10. In a water tube steam boiler of the bent tube type, three consecutively arranged upper steam and water drums including a rear steam offtake drum, a lower water chamber, a furnace from which heating gases pass between the drums, baffles dividing the gas spaceinto three gas passes separately extending from the water chamber toward the upper drums, three separate banks of tubes with each bank constituting substantially parallel tubes extending through one of said gas passes 'and substantially directly from said chamber to an upper drum, said separate banks diverging from the chamber to materially spaced positions beneath the upper drums to which they are respectively connected, cross-over tubes arranged in a bank and extending from the fore most steam and water drum directly toward a position immediately. beneath the middle steam and water drum and thence alongside the tubes of the middle bank, some of the cross-over tubes extending thence through the second gas pass in positions generally parallel to the tubes of the middle bank to the water chamber while the remainder similarly extend through the first gas pass immediately in front of the first bafile, a steam-ofitake connection leading from the rear upper drum, steam circulators directly connecting the steam spaces of the oiftake and middle upper drums, other steam circulators directly connecting the middle and front upper drums, said remainder of the cross-over tubes being disposed at a substantial distance rearwardly of the front bank of tubes, and a drainable superheater disposed between said remainder and the front bank.

HOWARD J. KERR; IVAR L. LANGVAND. 

